What is Btrfs?

Btrfs is a modern file system developed by multiple parties and now supported by select Synology NAS models. Btrfs was designed to address obstacles often encountered in enterprise storage systems, such as fault tolerance, management, and data protection.

What are the benefits of Btrfs?

Metadata mirroring and increased data availability

In any storage system, keeping metadata intact is critical as it includes important information, such as folder structures, filenames, access permissions, and the location of each file. Btrfs stores two copies of metadata on a volume, allowing for data recovery if the hard drive is damaged or suffers from bad sectors.

Btrfs file self-healing

Traditional storage systems might experience errors that go completely unnoticed which result in corrupt data being provided to applications with no warning or error messages. In order to avoid these types of errors, Btrfs provides checksums for data and metadata, generates two copies of metadata, and then verifies the checksums during each read process. Once discovering a mismatch (silent data corruption), the Btrfs file system is able to auto-detect corrupted files (silent data corruption) with mirrored metadata, and recover broken data using the supported RAID volumes, including RAID 1, RAID 5, RAID 6, RAID 10, F1, and SHR.

Snapshots and data protection

The Btrfs file system introduces a powerful snapshot feature allowing you to create a point-in-time copy of an entire shared folder. That way, if human error results in a lost or corrupt database, you can quickly restore the data back to the previous time at which the snapshot was captured.

Low impact, big benefit

Taking a snapshot consumes only a small amount of additional storage space, while exerting little impact on system performance thanks to Btrfs's copy-on-write architecture.

Frequent, scheduled backup

Automatically create point-in-time copies of data up to every 5 minutes without affecting performance, guaranteeing granular data backup and recovery.

Customizable retention policy

Instantaneous snapshots

Capture snapshots instantly and backup data without worrying about files being modified or deleted during the backup process.

Self-service recovery

Employees can view earlier versions of files and restore them to a previous state by themselves using File Station or Windows File Explorer.

Instant SMB/AFP server-side copy

Compared with the traditional server-side copy, which requires processing time, Btrfs fast-clone technology allows instant file copy to be achieved on File Station, SMB and AFP protocols if the source and destination are both on the same Btrfs volume.

Additional benefits of Btrfs

Using the Btrfs file system on your Synology NAS brings a wide variety of benefits to DiskStation Manager and Synology packages.

Efficient Drive storage

Compared to ext4 volumes, Btrfs does not require double the storage space for Drive's file versioning and history data. You can retain historical versions of files when using Drive — without worrying about consuming too much storage space.

Data consistency of backups

Traditional backup methods require time to copy data from one place to another, potentially leading to inconsistent data if files are modified during the backup process. Btrfs solves this issue by taking a snapshot before the backup process starts, and then copying the snapshot data to the backup destination — with no need to worry about files being modified, moved, or deleted.

Quotas for shared folders

Specify a storage limit for individuals shared folders, so your storage space will not be consumed by a particular shared folder. This is helpful for controlling available storage space when multiple teams or departments store files on the same Synology NAS server.

Clone entire shared folders

With Btrfs, you can simply select a shared folder and make a clone of all the contents nearly instantaneously. This is useful when testing updates to websites or databases and you need a quick clone.

Frequently Asked Questions

Do I need to configure anything special to take advantage of the data integrity features of Btrfs?

The metadata mirroring and checksum features are enabled by default on all Btrfs volumes. For files, the copy-on-write and checksum features are enabled by default, but can be switched off for best performance.

How do I create a Btrfs volume?

Open Storage Manager and create a new volume. You will be prompted to choose a file system (btrfs or ext4) during the creation process.

Where can I create and restore file from snapshots?

Snapshot Replication (available on Synology NAS models that support Btrfs) includes options to take snapshots on demand or configure schedules and retention policies. You can browse and restore snapshots using Snapshot Replication, File Station, Windows File Explorer, or other file protocols.